1. Field of the Invention
The present invention relates generally to wall structures, and in particular, baseboards or wall bases. The invention relates more specifically to an extruded plastic wall structure with a hollow core, and methods for making such a wall structure.
2. Description of Prior Art
Baseboards and wall bases are known in the art as molding or trim applied at the base of a wall to complete the intersection of the wall and the floor. These wall bases decorate as well as protect the wall from scuffing and impact from feet, vacuum cleaners, wheelchairs, dollies, wheeled furniture, etc. Furthermore, the wall bases protect the edge of the carpet or flooring adjacent to the wall. In addition, the wall base can hide unsightly electrical, telephone or other wires, protecting the wires from damage and preventing people from tripping over these wires or inadvertently touching them.
A variety of wall bases exist, including those made of wood, metal and plastic. Wood wall bases are generally more expensive than plastic, and wood is considered to be more elegant, elaborate and traditional. However, the look of wood can be successfully emulated or evoked with well-constructed plastic wall bases. Complex wall structure profiles can be extruded from plastic more easily than machined from wood. However, one disadvantage of using plastic is that solid plastic wall structures can be heavy, especially in contrast to wood wall bases. Extrusion molding of solid wall bases has additional problems. These solid wall bases are often quite thick and inflexible. Further, there may be warping or distortion due to uneven cooling of wall bases with uneven thicknesses and the solid, heavy, inflexible bases can be difficult to install. Moreover, warped or distorted wall bases may be unsightly.
Furthermore in regard to the extrusion process, flooring manufacturers have failed to produce a satisfactory wall base with a specific thickness. During Applicant's process of developing and testing samples of a wall base profile requested by a customer, the customer sought a company in the business of designing and manufacturing plastic wall bases and producing a hollow plastic wall base, and requested a cost estimate to produce such a wall base. The competitor could not provide such a cost estimate and stated it was beyond their capability to produce a hollow wall base. The failure of Applicant's competitor indicates the unobviousness of the present invention.
In contrast to solid wall bases, those comprising one or two parts, with covers, are often used in conditions in which it is desired to install and hide telephone, electrical or other wires. In these situations, the wires are placed under the cover of the wall base. For example, U.S. Pat. No. 5,598,681 discloses a baseboard made from a resin material. This baseboard has two parts, a backwall which abuts with a room wall and a front cover. A hollow exists between the backwall and the front cover, and wires, such as telephone or electric wires, can be installed in this hollow space. A problem with the prior art is that the baseboard is comprised of more than one part, making manufacturing, shipping and installation difficult and expensive.
U.S. Pat. No. 6,457,287 to Wilcox discloses a horizontally disposed when in use window sill cover having a hollow body with a lower wall and an upper wall. Interior support walls are disposed between the upper wall and the lower wall. This arrangement of the lower wall, the upper wall and interior support walls define air spaces within the body. A convex terminal portion is a semicircle in cross section with a hollow air space, which is connected to the body. The convex terminal portion has a vertically disposed portion for extending vertically over the edge of the window sill. The window sill cover of the '287 patent could never function as a wall base since it cannot lie flat against a wall. Furthermore, the window sill cover of the '287 patent has very thin walls, and would not be expected to withstand the impacts which would likely occur with wall bases. It is not known if the product disclosed in U.S. Pat. No. 6,457,287 was ever made.
On the contrary, in the various embodiments of the present wall structure, the rear wall of each section is flat from the bottom of the wall structure to the top of the wall structure. This flat rear wall section abuts the wall of the room where the wall structure is installed. Additionally, the contour of the rear wall of at least one section of the wall structure is different from the contour the front wall of at least one section of the wall structure, which is not the case with Wilcox. Furthermore, the wall thickness of the inventive products described below is able to withstand impacts expected to occur in wall structures.
There is a need for a wall structure which is lightweight, thinner than wood or solid plastic wall structure, contains a minimal number of parts, and is easy and cost effective to manufacture, to ship and to install. The present invention fills the need for such a wall structure in a unique manner.